Me too - I am 65 and coding all hours. At least half the time on tooling to encode the way I want to do things. I have ideas and implement them. I think it is fun as you make more progress. I do think it is a temporary phase and not sure if the next one will be as much fun or once I have drained the accumulated ideas that would be nice to do someday.

I feel selfish in that I am towards the end of my career rather than right at the start.